I recently (at least recent for me) noticed Keeppower started making 16340. I have used their 16650 in the past with much success. I am hesitant to try CR123a's again because every time I have used them eventually they destroy a flashlight. If anyone has used the Keeppower 16340 I would be interested to hear what they have to say.
So far the Sure Fire rechargeable 123 has been great. I get about 1-1.5 weeks out of each charge. I’ve got two batteries in rotation as needed. For day to day activities I cut standard CR123 batteries completely out with these and 18650’s.